Steam chest for radial flow steam turbines



L Nov. 23, 1965 A. G. PETERSSON 3,219,313

STEAM CHEST FOR RADIAL FLOW STEAM TURBINES 5 Sheets-Sheet 1 Filed April 26, 1963 ATTORNEYS I Nov. 23, 1965 A. G. PETERSSON 3,219,313

STEAM CHEST FOR RADIAL FLOW STEAM TURBINES Filed April 26, 1963 s Sheets-Sheet 2 I Nov. 23, 1965 A. G. PETERSSON 3,219,313

STEAM CHEST FOR RADIAL FLOW STEAM TURBINES Filed April 26, 1965 3 Sheets-Sheet 3 k INVENTOR BY Jaw 1mm) TTORNEE' United States Patent 3,219,313 STEAM CHEST FOR RADIAL FLOW STEAM TURBINES Axel Gunnar Petersson, Finspong, Sweden, assignor to Stal-Laval Turhin-Aktiebolag, Finspong, Sweden, a corporation of Sweden Filed Apr. 26, 1963, Ser. No. 275,983

Claims priority, application Sweden, May 17, 1962,

5,532/ 62 8 Claims. (Cl. 253-165) The present invention relates to steam turbines of the radial flow type and more particularly to so-called steam chests provided in combination with turbines of that type which are formed with separate sections for admitting and retracting steam of various pressures and temperatures to and from the rotary system of the turbines, respectively.

The object of the invention is to provide a steam chest of this type in which the steam passing through the admission section traverses gradually smaller areas of passage according as it approaches the rotary turbine system, whereas the steam passing through the retraction section traverses gradually larger areas of passage according as it withdraws from the rotary turbine system.

Another object of the invention is to provide a steam chest structure the admission and retraction sections of which are so related to each other as to secure a small axial dimension of the chest, while allowing steam admission pipes and steam retraction pipes to be connected to the respective sections in diametrical directions without giving rise to leakage or interfering with the flow of steam within the sections.

These objects are obtained according to the invention by dividing the interior of the chest into sections by means of a helical partition or partitions extending substantially radially with relation to the cylindrical shell forming the circumferential wall of the chest.

The above stated and other objects and features of the invention will be more nearly set forth in the description hereinafter to follow, reference being had to the accompanying drawing, in which the invention is shown as applied to a preferred form of steam chest of a type comprising in combination an outer cylindrical shell, an inner cylindrical shell, and end walls covering the space between said shells at both ends thereof.

In the drawing:

FIG. 1 is a perspective View of the steam chest with one end wall and part of a helical partition removed. FIG. 2 is a cross-section along line II of FIG. 5. FIGS. 3, 4 and are sections along lines IIIIII, IVIV and V--V, respectively of FIG. 2. FIG. 6 is a perspective view of the steam chest with one end wall and the outer shell and a helical partition removed.

'FIG. 7 is an axial section of a radial flow turbine having side plates according to the invention.

In the drawing the reference numeral 1 designates the end wall of the chest facing the rotary elements of the turbine. Formed in said end wall are openings for admission and extraction of steam, to and from the rotary elements of the turbine, respectively. The steam admission openings are provided with guide vanes or similar means for increasing the velocity component as imparted to the steam while passing through the chest. Said component is equally directed as the peripheral speed of the rotary elements of the turbine. Reference numeral 2 designates the cylindrical outer shell and 3 is the end wall of the steam chest remote from the turbine. In FIG. 1 said end wall 3 is removed in order to show the inner elements of the chest comprising two concentrically arranged cylindrical walls 4 and 5 the axial length of which 3,ZlQ,3l3 Patented Nov. 23, 1965 increases gradually along their circumference, as reckoned from one side to the other of a radial partition 6 inserted between the outer shell 2 and an inner shell 7 surrounding the turbine shaft D, E. In the drawing, the gradually varying axial length of the walls 4- and 5 is obtained by forming the edges of the walls shown in FIG. 1 as upper edges along helical lines.

Bearing on said helical edges of walls 4 and 5 is a corresponding helical partition 8, extending radially between cylindrical wall 4 and outer shell .2 and circumferentially from one side to the other of the radial partition 6.

By said helical partition 8 the steam chest is divided axially into a steam admission section on the side of partition 8 remote from the turbine and a steam extraction section on the other side of partition '8. The steam ad mission section forms a single chamber 9, whereas the steam retraction section comprises two concentric annular chambers 10 and 11, the former located between the cylindrical walls 4 and 5 and the latter located between cylindrical wall 5 and outer shell 2.

Steam is admitted to chamber 9 through pipes 1% and 13 and openings 14 and 15, formed in the outer shell 2. The extraction steam is drawn off from chambers 10 and 11 through pipe-s 16 and 17, respectively, connected to openings in the outer shell. The steam admission chamber 9 is an area of flow gradually decreasing from inlet 14 or inlets 14 and 15, and the extraction chambers 10 and 11 are an area of flow gradually increasing towards their outlets.

The steam admission chamber 9 communicates with admission openings 19 (FIGS. 2-5 and 7), leading to the rotary system formed in end wall 1, by way of an annular passage 18 extending around the inner shell 7. Steam extracted from the turbine is passed to the chambers 10 and 11 via openings 20 in the end wall 1. Provided inside the inner shell 7 is a shaft gland I (FIG. 7). Leakage through this gland is passed via a chamber 21, FIG. 3, to a leak-olf collector 22, from where it is drained otf through a pipe 23 connected to an opening 24 in the collector 22.

Reference numeral 25 designates an additional extraction opening from chamber 11.

As an alternative, the end wall 1 facing the rotary elements of the turbine may have a restricted radial extension, viz. from inner Wall 7 to the cylindrical wall 4, so as to cover an area corresponding to that of the annular passage 18. As a result, the concentrically arranged extraction openings 20 will be replaced by annular openings bounded by the cylindrical walls 4 and 5 and the cylindrical outer shell 2.

In order to more efliciently isolate the admission and retraction sections from each other the steam chest may be divided into two quite separate axial halves, one including the admission section and the other including the retraction section, with each section having at its end facing the plane of division a helical wall like 8. In assembling these two halves with their respective helical walls 8 facing each other provisions may be made to leave a closed space between said walls 8 which may be evacuated with a view to prevent heat transmission between the sections.

I claim:

1. In a steam chest for radial flow turbines having separate sections for admission and retraction of steam of various pressures and temperatures to and from the rotary system of the turbine, the provision of means for dividing the chest into two axially spaced sections of gradually varying areas of flow, viz. a steam admission section having an area of flow gradually decreasing from inlet to outlet of the section and a steam retraction section having an area of flow gradually increasing from inlet to outlet of the section.

2. In a steam chest as claimed in claim 1 which is provided with a cylindrical housing, the provision inside said housing of a helical partition extending substantially radially with relation to said housing, which divides the interior of the chest into a steam admission section on one side of said partition and a steam retraction section on the other side of the partition.

3. In a steam chest as claimed in claim 1 which is provided with a cylindrical housing, the provision of two axially spaced helical partitions for dividing the interior of the chest into a steam admission section and a steam retraction section, the space between said partitions being evacuated for heat insulating purpose.

4. In a steam chest comprising a cylindrical outer shell, a cylindrical inner shell, end walls for covering the space between said shells at both ends thereof, a radial partition provided between said shells along the entire length thereof, a helical partition extending all around the inside of the outer shell from one side of said radial partition to the other side thereof for dividing the space between the two shells into a steam admission section on its one side and a steam retraction section on its other side, and cylindrical walls extending within the steam retraction section between opposite sides of the radial partition for dividing said section into two concentric annular chambers, having areas of flow increasing from on one side :of the radial partition to the other side thereof, the outer shell being formed with outlets leading from the annular steam retraction chambers on said other side of the radial partition.

5. In a steam chest as claimed in claim 4, and in which the helical partition extends radially between the outer shell of the chest and the innermost one of the cylindrical walls in the steam extraction section, the further feature that said innermost cylindrical wall is provided at a distance from the inner shell of the chest so as to leave an annular passage between itself and said inner shell for exposing an annular portion of the end wall of the chest facing the rotary turbine system to the steam admission chamber.

6. In a steam chest as claimed in claim 5 the further feature that said annular end wall portion exposed to the steam admission chamber is formed with a circular row of admission apertures, other circular rows of apertures being formed in said end wall concentrically surrounding the first-mentioned row for delivering steam from the rotary turbine system to the steam retraction chambers.

"7. In a steam chest as claimed in claim 6 the provision of steam :guide elements in the circular row of steam admission apertures.

8. In a steam chest as claimed in claim 4, in which the end wall facing the turbine extends radially between the inner shell and the innermost one of the cylindrical walls provided in the steam retraction section so as to bring the extraction chambers into unrestricted communication with the rotary turbine system.

No references cited.

KARL J. ALBRECHT, Primary Examiner.

JOSEPH H. BRANSON, 111., Examiner. 

1. IN A STEAM CHEST FOR RADIAL FLOW TURBINES HAVING SEPARATE SECTIONS FOR ADMISSION AND RETRACTION OF STEAM OF VARIOUS PRESSURES AND TEMPERATURES TO AND FROM THE ROTARY SYSTEM OF THE TURBINE, THE PROVISION OF MEANS FOR DIVIDING THE CHEST INTO TWO AXIALLY SPACED SECTIONS OF GRADUALLY VARYING AREAS OF FLOW, VIZ. A STEAM ADMISSION SECTION HAVING AN AREAW OF FLOW GRADUALLY DECREASING FROM INLET TO OUTLET OF THE SECTION AND A STEAM RETRACTION SECTION HAVING AN AREA OF FLOW GRADUALLY INCREASING FROM INLET TO OUTLET OF THE SECTION. 